Initial move

frontend/src/events/messaging-system.ts

@@ -0,0 +1,60 @@
+export type Message<T> = {
+    type: string,
+    data?: T,
+};
+
+export type MessageHandler<T> = (message: Message<T>) => void;
+
+export class MessagingSystem {
+    private handlers: Record<string, MessageHandler<any>[]> = {};
+
+    public registerHandler<T>(type: string, handler: MessageHandler<T>): void {
+        if (!this.handlers[type]) {
+            this.handlers[type] = [];
+        }
+        if (!this.handlers[type].includes(handler)) {
+            this.handlers[type].push(handler);
+        }
+    }
+
+    public unregisterHandler<T>(type: string, handler: MessageHandler<T>): void {
+        if (this.handlers[type]) {
+            this.handlers[type] = this.handlers[type].filter(h => h !== handler);
+        }
+    }
+
+    public registerHandlerOnce<T>(type: string, handler: MessageHandler<T>): void {
+        const wrappedHandler = (message: Message<T>) => {
+            handler(message);
+            this.unregisterHandler(type, wrappedHandler);
+        };
+        this.registerHandler(type, wrappedHandler);
+    }
+
+    public waitForMessage<T>(type: string, timeout?: number): Promise<T> {
+        return new Promise((resolve, reject) => {
+            const handler = (message: Message<T>) => {
+                if (timer) clearTimeout(timer);
+                resolve(message.data!);
+                this.unregisterHandler(type, handler);
+            };
+
+            this.registerHandler(type, handler);
+
+            let timer: ReturnType<typeof setTimeout> | undefined;
+            if (timeout) {
+                timer = setTimeout(() => {
+                    this.unregisterHandler(type, handler);
+                    reject(new Error(`Timeout waiting for message of type '${type}'`));
+                }, timeout);
+            }
+        });
+    }
+
+    public sendMessage<T>(message: Message<T>): void {
+        const handlers = this.handlers[message.type];
+        if (handlers) {
+            handlers.forEach(handler => handler(message));
+        }
+    }
+}